Today | Weather | Tuesday, October 21, 2025

Weather in Castle Rock, Colorado

10:34 PM
Now
Night
45° F
Feels Like 41°
Precipitation 0 %
Wind 6 mph
Humidity 35 %
Today
Night
Day 72°
Night 36°
Precipitation 0 %
Wind 6 mph

Castle Rock Weather Forecast Updated

37 minutes ago
Last updated on

Weather Forecast History

Last Year's Weather on This Day (October 21, 2024)

Day

66°

Night

45°

Air Quality in Castle Rock

NOW
28 AQI
Good air quality Dominant pollutant: O3

Pollutant Concentrations:

PM2.5 1.47 µg/m³
PM10 1.97 µg/m³
O3 0.030 ppm
NO2 2 ppb
SO2 0 ppb
CO 0.10 ppm
NH3 0.88 µg/m³
NO 0 µg/m³
PM2.5 – Fine particles <2.5μm
PM10 – Inhalable particles <10μm
O3 – Ozone
NO2 – Nitrogen dioxide
SO2 – Sulfur dioxide
CO – Carbon monoxide
NH3 – Ammonia
NO – Nitric oxide

Health Recommendations:

Air quality is considered satisfactory, and air pollution poses little or no risk.

Show raw pollutant concentrations (µg/m³)
PM2.51.47 µg/m³
PM101.97 µg/m³
O358.46 µg/m³
NO23.83 µg/m³
SO20.08 µg/m³
CO110.45 µg/m³
NH30.88 µg/m³
NO0 µg/m³